Binding affinity and mode of distamycin A with A/T stretches in double-stranded DNA: importance of the terminal A/T residues.

Distamycin A (Dst) is an antibiotic which binds to the minor groove of double-stranded DNA at A/T-rich regions. We have examined the affinity and mode of Dst binding to DNA duplexes containing a conserved A/T core and variable terminal A/T regions by using circular dichroism spectroscopy. The observed circular dichroism spectra were analyzed by singular value decomposition and fitted to a two-step binding model.

Increase in peripheral CD4 bright+ CD8 dull+ T cells in Parkinson disease.

Background: Immune abnormalities are known to be involved in the pathogenesis of sporadic Parkinson disease.

Objective: To examine whether abnormalities in peripheral lymphocytes exist in Parkinson disease.

Methods: Immune mediators, including CD1a, CD3, CD4, CD8, CD45RO, and Fas (CD95), were examined in peripheral lymphocytes of patients by 3-color flow cytometry.

Effect of heparin on hemagglutination by pseudorabies virus.

Heparin inhibited hemagglutination (HA) by pseudorabies virus (PRV), but not HA by Akabane virus, bovine adenovirus type 7, Fukuoka virus, Getah virus, Japanese encephalitis virus, and parainfluenza virus type 3 belonging to the families Bunyaviridae, Adenoviridae, Rhabdoviridae, Togaviridae, Flavivi-idae, and Paramyxoviridae, respectively. The minimal inhibitory concentration of heparin required to inhibit 8 HA U of PRV ranged from 0.005 to 0.

Physicochemical properties of transmissible gastroenteritis virus hemagglutinin.

Transmissible gastroenteritis virus was readily adsorbed onto chicken erythrocytes at 4 degrees C. The hemagglutinin thus adsorbed could be eluted from the erythrocytes by incubating in phosphate buffered saline at 37 degrees C. The receptor on chicken erythrocytes for the hemagglutinin was inactivated by neuraminidase and potassium periodate, but not by trypsin, 2-mercaptoethanol and formalin.

Hemagglutination with transmissible gastroenteritis virus.

Transmissible gastroenteritis virus grown in primary swine kidney cell cultures agglutinated erythrocytes from chicken, guinea pig and cattle but not erythrocytes from mouse and goose. The optimal incubation temperature was at 4 degrees C. The hemagglutination (HA) reaction was inhibited by specific antiserum.

Detection of transmissible gastroenteritis virus in feces from pigs by reversed passive hemagglutination.

A reversed passive hemagglutination (RPHA) method was developed for the detection of transmissible gastroenteritis (TGE) virus in the fecal specimens from pigs. Ovine erythrocytes fixed with glutaraldehyde and treated with tannic acid were coated with anti-TGE virus swine antibodies, which were purified by affinity chromatographic technique linked with purified TGE virus. The RPHA test was done by the Microtiter method.

Protective effect of acidic mannan fraction of bakers' yeast on experimental candidiasis in mice.

An acidic fraction of bakers' yeast mannan, WAM025, showed a significant protective effect against Candida albicans infection in mice, but a neutral fraction of the same bakers' yeast mannan, WNM, did not exhibit this effect. Moreover, pretreatment with WAM025 resulted in a marked reduction of proliferation of C. albicans cells in the organs of the infected mice.

Detection of bovine coronavirus in feces by reversed passive hemagglutination.

A reversed passive hemagglutination (RPHA) method was developed for the detection of bovine coronavirus in fecal specimens. Sheep erythrocytes fixed with glutaraldehyde, and then treated with tannic acid were coated with anti-bovine coronavirus rabbit antibodies purified by affinity chromatography using bovine coronavirus linked to Sepharose 4B. The RPHA test was carried out by a microtiter method.

Incompatibility of citrate utilization plasmids isolated from Escherichia coli.

The 57 conjugative Cit plasmids isolated from 72 citrate-utilizing (Cit+) Escherichia coli strains from various sources were classified into four groups on the basis of their genetic properties. Escherichia coli K13 strains carrying these Cit plasmids could utilize cis-aconitate or tricarballylate, in addition to citrate.

Propagation of the Kakegawa strain of bovine coronavirus in suckling mice, rats and hamsters.

The Kakegawa strain of bovine coronavirus was easily propagated in suckling mice. Infected animals died with nervous symptoms, and serial passage was readily accomplished by intracerebral inoculation with brain emulsions. The 3rd passage viral material from infected mice evoked the same disease in suckling mice, rats and hamsters inoculated by the intracerebral or by the subcutaneous route.

Spontaneous emergence of an Hfr strain with a cit plasmid from natural isolates of citrate-positive Escherichia coli bovine origin.

From citrate-utilizing (Cit+) Escherichia coli strain C53 of bovine origin, strains C53A and C53B were obtained. Upon mating with recA+ but not with recA mutant recipients of K-12, C53A produced chromosomal recombinants at quite high frequencies, leading to the following conclusions: (i) C53A is an Hfr strain; (ii) the site of integration of the Cit plasmid (IncH1) is between metA (89 min) and ara (1 min); (iii) the direction of chromosome transfer is clockwise; and (iv) the plasmid-associated determinants are transferred as the terminal markers. A transductant of a dnaA(Ts) strain, CRT46, which acquired Cit determinants from a recombinant, SG13, was also an Hfr strain similar to SG13, and thermoresistant due to suppressive integration.

Detection of conjugative R plasmids conferring chloramphenicol resistance in Escherichia coli isolated from domestic and feral pigeons and crows.

A total of 87 domestic pigeons of 2 lots and 184 feral pigeons of 15 lots were examined from 1975 to 1977 for the presence of drug-resistant (especially chloramphenicol resistant) Escherichia coli. 20 (23.0%) of the domestic pigeons of the 2 lots, and 39 (21.